Isolation and characterization of mutants of the citrus canker pathogen <i>Xanthomonas axonopodis</i> pv. <i>citri</i> that induce a distinct pattern of disease
Bibliographic record
Abstract
Random mutagenesis with the transposon Tn5tac1 in Xanthomonas axonopodis pathovar citri, the causal agent of citrus canker, generated four mutants with altered pathogenicity. These mutants were classified into three groups: (i) the nonpathogenic (NP) mutants XT10 and XT122, which did not induce any visible symptoms in the host; (ii) the WS - mutant XT27, which induced a callus-like lesion but not a watersoaked lesion; and (iii) the CL - mutant XT37, which was unable to induce a callus-like eruption but did induce the formation of a watersoaked lesion around the infection site. The NP mutants failed to grow in planta, whereas the WS - and CL - mutants showed a reduced growth rate relative to that of the wild type. Co-inoculation of leaves with the WS - and CL - mutants did not result in complementation of their respective defects. The extent of extracellular accumulation of polysaccharide, protease, and amylase activities by each of the mutants was similar to that of the wild type. The extracellular activity of polygalacturonate lyase of XT27 was reduced relative to that of the wild type and other mutants. Unlike the wild type and other mutants, XT27 also required glutamic acid for growth in culture. Southern blot hybridization revealed that each of the mutants resulted from transposon insertion at a single site; the insertion sites for XT10 and XT27 were located in the chromosome, whereas those for XT37 and XT122 were located in the indigenous plasmids. These results provide evidence that bacterial genes contribute independently to the pathogenesis of citrus canker.Key words: citrus canker, pathogenicity genes, transposon mutagenesis.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one teacher head, not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".